How to collect test coverage including untested files?

[DanilAgafonov]

Is it possible to include untested files in coverage report?

Reason: I want to know how much code I have uncovered in my project overall. I want to see files for which I haven't created any tests and never imported them anywhere.

Example:
Let's say I have src/index.js file. And I run node --test --experimental-test-coverage --test-coverage-include="src/**/*" in the root of my project. My expectation: report should include index.js showing that zero lines covered with tests.

[nullswan]

Also interested ! I think this is related to #4487

[MoLow]

Coverage is collected using v8's takeCoverage method, which means it is only aware of code that has actually run.
this might be a feature that is possible to implement but it is impossible with the current implementation

[hernandemonteiro]

[DanilAgafonov]

Thanks for a detailed reply.

I've actually been considering doing something like import './src/index.js'; in test setup file. But I don't think this is option I want to use, because if I do that, the top-level code in these imported modules will be executed and marked as "test covered" (which I don't want). I want these never-imported modules be marked as untested/uncovered (I mean it should report that zero lines was executed during test in these files).

[rwalle]

Is this AI generated answer? It is almost completely irrelevant.

Use --test-coverage-include to include all files (you are already doing this):

If they are already doing this, why do you even bring this up???

If the files are still not included, consider importing them in a "setup" file to ensure they are loaded into the test environment.

How do you include these files? You need to come up with a list with precisely the files you want, which is difficult or at least very cumbersome to maintain. You need some sort of tool to automatically generate the list and make sure it is always up-to-date, possibly as part of a build step. And even so there are likely issues that could arise with this approach.

Mentioning nyc/istanbul and jest when people are clearly talking about the built-in test runner is also ridiculous.

This answer makes zero sense.

[avivkeller]

Just a reminder that this discussion is about the Node.js native test runner, not Jest.